This invention relates to a method of construction of concrete decks utilizing precast members over which concrete is poured to form a monolithic structure. The invention is directed to a construction procedure providing for lighter weight supporting beams extending between supporting columns.
In known construction techniques utilizing precast members, such as that commonly referred to as the Filigree Wideslab Method, it has been considered preferable to utilize such members having a substantially constant thickness in order to simplify manufacture and transportation of the members. Conventionally, the structure has been formed by the placement of a plurality of beam members, with individual such beams extending between adjacent supporting columns in a row of such columns, with the longitudinal ends of the beams resting or placed adjacent the uppermost end of each respective column. Then, a plurality of precast slabs are placed extending between the respective rows of the beams, with the longitudinal ends of each slab overlapping the edges of the beams. When concrete is then poured over the entire structure, a concrete deck is formed having beams of generally uniform thickness supporting the deck.
While this construction may prove satisfactory in many respects, it suffers several inherent deficiencies. First, because stresses on the beam caused by wind loading and the weight of the deck are greatest adjacent the supporting columns, it is necessary that the beams be thick enough where they join the columns to support those loads. However, toward the center of the span of each beam the strength and thickness required of the beam is considerably less, such that conventional beams are overdesigned and represent both a waste of construction materials and excess weight to be supported by the structure. Additionally, the conventional construction method requires that each beam member be aligned with substantial precision over the uppermost extremity of each of its respective supporting columns.